An organization may have control over allocation of a block of Internet Protocol addresses (or other identifiers). The organization may allocate these IP addresses to various entities, such as customers of the organization. Because the computing needs of an entity may change, the quantity of IP addresses allocated to that entity by the organization may vary over time. Eventually, as addresses are allocated and deallocated across the various entities, the IP addresses may become fragmented. That is, one or more of the IP addresses allocated to a particular entity may not be contiguous with other IP addresses allocated to that entity.